When graphite crucibles are used to melt reactive metals and rare earth alloys, carbon contamination and sticking are the two problems that ruin a melt. A plasma sprayed yttria (Y2O3) coating forms a stable, non-wetting barrier between the graphite and the melt.
Yttria is chosen for the most aggressive melts because it has excellent thermal stability and very low reactivity with molten metals. It is applied by plasma spraying in a controlled atmosphere to keep the coating pure.
We coat crucibles, moulds and nozzles for vacuum melting, sintering and powder metallurgy customers.
